Diatoms of North AmericaDiatoms of North America

Gliwiczia calcar

(Cleve) Kulikovskiy, Lange-Bert. and Witkowski 2013

Planothidium Calcar Guide
  • Category
    Monoraphid
  • Length Range
    9.7-21.2 µm
  • Width Range
    7.1-10.4 µm
  • Striae in 10 µm
    26-32
  • Synonyms
    Achnanthes calcar Cleve 1891
    Planothidium calcar Edlund in Edlund, Soninkhishig, Williams and Stoermer 2001

Identification

Gliwiczia calcar LM7 Gliwiczia calcar LM3 Gliwiczia calcar LM6 Gliwiczia calcar LM4 Gliwiczia calcar LM2 Gliwiczia calcar LM5 Gliwiczia calcar LM1
View image metadata
Gliwiczia calcar SEM1

Description

Valves are elliptic, although they may be slightly constricted in the center. The axial area is narrow and linear on the raphe valve; the axial area is narrow and rhomboid on the rapheless valve. The central area on both valves is asymmetric, expanded to valve margins and contains a cavum. The raphe is straight with sigmoid terminal fissures. The striae are fine, uniseriate and radiate throughout both valves.

Autecology

This taxon has been reported with light micrographs from Alaska (Foged 1981), northwestern Québec (Fallu et al. 2000), Rocky Mountains and Cascades (Bahls 2021).

In the Great Lakes National Parks (Edlund et al. 2009, 2011, 2012, 2013), this taxon is rare (0.1-1% abundance) at Pictured Rocks (Beaver Lake) and Isle Royale (Richie Lake).

This taxon is reported to occur in mountain lakes and streams with cold, alkaline water of very low conductivity and nutrient content (Bahls 2021).

Several research groups consider this taxon an indicator organism and published regional environmental optima and tolerances including:

Bahls (2021): Conductivity - 61 µS/cm, pH - 7.5, Temperature - 9.7°C, Total Nitrogen - 0.17 mg/L, Total Phosphorus - 9 µg/L for populations from the Rocky Mountains and Cascades.

Original Description

A. Calcar Cl. - Upper valve broadly elliptic, 0,012 m. m. in length and 0,009 m. m. in breadth, with about 24 striae in 0,01 m. m. It carries on the one side a horseshoe-like thickening, which is prolonged on the other half of the valve into a spur-like projection. The lower valve is not known with certainty, but in the same gathering, in which this species has been found, occurs a valve of similar outline and size, the striæ of which reach the raphe and are 25 in 0,01 m. m. That valve, which has a great resemblance to Diadesmis lucidula Grun. (V. H. XIV, 40) may possibly be the lower valve of A. Calcar. Pl. III, fig. 8, (9 ?). Ab. 45, 47.

  • Basionym
    Achnanthes calcar
  • Author
    Cleve 1891
  • Length Range
    12 µm
  • Width
    9 µm
  • Striae in 10µm
    24

Original Images

Plcalcar Orig Ill
Plcalcar Orig Descr

Citations & Links

Citations

Links

  • Index Nominum Algarum
    Original
  • North American Diatom Ecological Database
    NADED ID: 155033

Updates

Apr 06, 2016 - Transfer from Planothidium

The taxon, Planothidium calcar Edlund in Edlund, Soninkhishig, Williams and Stoermer 2001 appeared on this page. (Note that the citation missed attribution to Cleve). As of this date, the name and authorshop is shown as Gliwiczia calcar (Cleve) Kulikovskiy, Lange-Bertalot and Witkowski. - S. Spaulding

Feb 05, 2026 - Addition of Autecology

From 2011 until 2026, the autecological information on this taxon page was limited. As of this update, information on ecology, biogeography, and environmental optima have been added. - Lane Allen and Mark Edlund

Cite This Page

Potapova, M., Edlund, M., Allen, L. (2011). Gliwiczia calcar. In Diatoms of North America. Retrieved March 23, 2026, from https://diatoms.org/species/47131/gliwiczia_calcar

Responses

The 15 response plots show an environmental variable (x axis) against the relative abundance (y axis) of Gliwiczia calcar from all the stream reaches where it was present. Note that the relative abundance scale is the same on each plot. Explanation of each environmental variable and units are as follows:

ELEVATION = stream reach elevation (meters)
STRAHLER = distribution plot of the Strahler Stream Order
SLOPE = stream reach gradient (degrees)
W1_HALL = an index that is a measure of streamside (riparian) human activity that ranges from 0 - 10, with a value of 0 indicating of minimal disturbance to a value of 10 indicating severe disturbance.
PHSTVL = pH measured in a sealed syringe sample (pH units)
log_COND = log concentration of specific conductivity (µS/cm)
log_PTL = log concentration of total phosphorus (µg/L)
log_NO3 = log concentration of nitrate (µeq/L)
log_DOC = log concentration of dissolved organic carbon (mg/L)
log_SIO2 = log concentration of silicon (mg/L)
log_NA = log concentration of sodium (µeq/L)
log_HCO3 = log concentration of the bicarbonate ion (µeq/L)
EMBED = percent of the stream substrate that is embedded by sand and fine sediment
log_TURBIDITY = log of turbidity, a measure of cloudiness of water, in nephelometric turbidity units (NTU).
DISTOT = an index of total human disturbance in the watershed that ranges from 1 - 100, with a value of 0 indicating of minimal disturbance to a value of 100 indicating severe disturbance.